A digital video recorder (DVR) allows a user to record video programming to a recordable medium, and to play back the recorded programs. The recordable medium in a DVR is typically a disk drive (also known as a “hard disk” or a “hard drive”). Before a video program is recorded, it is digitally encoded, which occurs at a fixed rate. On play back, video decoding also occurs at a fixed rate. To function properly, a DVR disk drive should be able to complete read or write requests at a sustained threshold rate which is related to the encoding/decoding rate. If the performance of the DVR disk drive is below this threshold, the quality of the recording will be adversely affected, and in some cases the DVR will not be usable for recording and/or playback.
Performance testing of DVR disk drives can be performed at the factory, before the disk is deployed. However, disk drive performance depends on the physical conditions under which it is used (e.g., temperature) and can degrade over time. Therefore, a disk which passed the performance test at the factory may later fail at the consumer location. Also, factory testing is not helpful for units that have already been deployed. Thus, a need arises to address the above-mentioned problems, among others.